diff --git a/sith.py b/sith.py
new file mode 100755
index 00000000..dbde8a84
--- /dev/null
+++ b/sith.py
@@ -0,0 +1,290 @@
+#!/usr/bin/env python
+
+"""
+Sith attacks (and helps debugging) Jedi.
+
+Randomly search Python files and run Jedi on it.  Exception and used
+arguments are recorded to ``./record.josn`` (specified by --record)::
+
+    %(prog)s random
+
+Redo recorded exception::
+
+    %(prog)s redo
+
+Fallback to pdb when error is raised::
+
+    %(prog)s --pdb random
+    %(prog)s --pdb redo
+
+"""
+
+from __future__ import print_function
+import json
+import os
+import random
+import sys
+import traceback
+
+try:
+    from itertools import izip as zip
+except ImportError:
+    pass
+
+import jedi
+
+
+class SourceCode(object):
+
+    def __init__(self, path):
+        self.path = path
+        with open(path) as f:
+            self.source = f.read()
+        self.lines = self.source.splitlines()
+        self.maxline = len(self.lines)
+
+    def choose_script_args(self):
+        line = random.randint(1, self.maxline)
+        column = random.randint(0, len(self.lines[line - 1]))
+        return (self.source, line, column, self.path)
+
+
+class SourceFinder(object):
+
+    def __init__(self, rootpath):
+        self.rootpath = rootpath
+        self.files = list(self.search_files())
+
+    def search_files(self):
+        for root, dirnames, filenames in os.walk(self.rootpath):
+            for name in filenames:
+                if name.endswith('.py'):
+                    yield os.path.join(root, name)
+
+    def choose_source(self):
+        # FIXME: try same file for several times
+        return SourceCode(random.choice(self.files))
+
+
+class BaseAttacker(object):
+
+    def __init__(self):
+        self.record = {'data': []}
+
+    def attack(self, operation, *args):
+        script = jedi.Script(*args)
+        op = getattr(script, operation)
+        op()
+
+    def add_record(self, exc_info, operation, args):
+        (_type, value, tb) = exc_info
+        self.record['data'].append({
+            'traceback': traceback.format_tb(tb),
+            'error': repr(value),
+            'operation': operation,
+            'args': args,
+        })
+
+    def get_record(self, recid):
+        return self.record['data'][recid]
+
+    def save_record(self, path):
+        with open(path, 'w') as f:
+            json.dump(self.record, f)
+
+    def load_record(self, path):
+        with open(path) as f:
+            self.record = json.load(f)
+            return self.record
+
+    def add_arguments(self, parser):
+        parser.set_defaults(func=self.do_run)
+
+    def get_help(self):
+        for line in self.__doc__.splitlines():
+            line = line.strip()
+            if line:
+                return line
+
+
+class MixinPrinter(object):
+
+    def print_record(self, recid=-1):
+        data = self.get_record(recid)
+        print(*data['traceback'], end='')
+        print("""
+{error} is raised by running Script(...).{operation}() with
+line  : {args[1]}
+column: {args[2]}
+path  : {args[3]}
+""".format(**data))
+
+
+class MixinLoader(object):
+
+    def add_arguments(self, parser):
+        super(MixinLoader, self).add_arguments(parser)
+        parser = parser.add_argument(
+            'recid', default=0, nargs='?', type=int, help="""
+            This option currently has no effect as random attack record
+            only one error.
+            """)
+
+    def do_run(self, record, recid):
+        self.load_record(record)
+
+
+class AttackReporter(object):
+
+    def __init__(self):
+        self.tries = 0
+        self.errors = 0
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        self.tries += 1
+        sys.stderr.write('.')
+        sys.stderr.flush()
+        return self.tries
+
+    next = __next__
+
+    def error(self):
+        self.errors += 1
+        sys.stderr.write('\n')
+        sys.stderr.flush()
+        print('{0}th error is encountered after {1} tries.'
+              .format(self.errors, self.tries))
+
+
+class RandomAtaccker(MixinPrinter, BaseAttacker):
+
+    """
+    Randomly run Script().<method>() against files under <rootpath>.
+    """
+
+    operations = [
+        'completions', 'goto_assignments', 'goto_definitions', 'usages',
+        'call_signatures']
+
+    def choose_operation(self):
+        return random.choice(self.operations)
+
+    def generate_attacks(self, maxtries, finder):
+        for _ in range(maxtries):
+            src = finder.choose_source()
+            operation = self.choose_operation()
+            yield (operation, src.choose_script_args())
+
+    def do_run(self, record, rootpath, maxtries):
+        finder = SourceFinder(rootpath)
+        reporter = AttackReporter()
+        for (operation, args) in self.generate_attacks(maxtries, finder):
+            reporter.next()
+            try:
+                self.attack(operation, *args)
+            except jedi.NotFoundError:
+                pass
+            except Exception:
+                self.add_record(sys.exc_info(), operation, args)
+                reporter.error()
+                self.print_record()
+                raise
+            finally:
+                self.save_record(record)
+
+    def add_arguments(self, parser):
+        super(RandomAtaccker, self).add_arguments(parser)
+        parser.add_argument(
+            '--maxtries', '-l', default=10000, type=int)
+        parser.add_argument(
+            'rootpath', default='.', nargs='?',
+            help='root directory to look for Python files.')
+
+
+class RedoAttacker(MixinLoader, BaseAttacker):
+
+    """
+    Redo recorded attack.
+    """
+
+    def do_run(self, record, recid):
+        super(RedoAttacker, self).do_run(record, recid)
+        data = self.get_record(recid)
+        self.attack(data['operation'], *data['args'])
+
+
+class ShowRecord(MixinLoader, MixinPrinter, BaseAttacker):
+
+    """
+    Show recorded errors.
+    """
+
+    def do_run(self, record, recid):
+        super(ShowRecord, self).do_run(record, recid)
+        self.print_record()
+
+
+class AttackApp(object):
+
+    def __init__(self):
+        self.parsers = []
+        self.attackers = []
+
+    def run(self, args=None):
+        parser = self.get_parser()
+        self.do_run(**vars(parser.parse_args(args)))
+
+    def do_run(self, func, debugger, **kwds):
+        try:
+            func(**kwds)
+        except:
+            exc_info = sys.exc_info()
+            if debugger == 'pdb':
+                import pdb
+                pdb.post_mortem(exc_info[2])
+            elif debugger == 'ipdb':
+                import ipdb
+                ipdb.post_mortem(exc_info[2])
+
+    def add_parser(self, attacker_class, *args, **kwds):
+        attacker = attacker_class()
+        parser = self.subparsers.add_parser(
+            *args,
+            help=attacker.get_help(),
+            description=attacker.__doc__,
+            **kwds)
+        attacker.add_arguments(parser)
+
+        # Not required, just fore debugging:
+        self.parsers.append(parser)
+        self.attackers.append(attacker)
+
+    def get_parser(self):
+        import argparse
+        parser = argparse.ArgumentParser(
+            formatter_class=argparse.RawDescriptionHelpFormatter,
+            description=__doc__)
+        parser.add_argument(
+            '--record', '-R', default='record.json',
+            help='Exceptions are recorded in here (default: %(default)s).')
+        parser.add_argument(
+            '--pdb', dest='debugger', const='pdb', action='store_const',
+            help="Launch pdb when error is raised.")
+        parser.add_argument(
+            '--ipdb', dest='debugger', const='ipdb', action='store_const',
+            help="Launch ipdb when error is raised.")
+
+        self.subparsers = parser.add_subparsers()
+        self.add_parser(RandomAtaccker, 'random')
+        self.add_parser(RedoAttacker, 'redo')
+        self.add_parser(ShowRecord, 'show')
+
+        return parser
+
+
+if __name__ == '__main__':
+    app = AttackApp()
+    app.run()